________is helpful to our environment.
Beijing has got_____ population of more than 13.8 million.
“Everybody is playing basketball outside. Can I join them, Dad? ”“_____________, you must finish your homework first. ”
“What are you doing , Amy?” “I want to ________ these pictures on the wall.”
“Can you teach me how to sing the song YOU AND ME ?” “_________”
“How long does it take you ________to Beijing?” “More than three hours.”